Special Marine Warning 21, NWS Anchorage, AK

AREA FORECAST DISCUSSION...CORRECTED
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM ADT SUN AUG 21 2005

.DISCUSSION...

SATELLITE THIS MORNING SHOWS A SIGNIFICANT TROUGH PUSHING ACROSS THE
STATE FROM THE EASTERN BERING.  300MB FLOW SHOWS THE MAIN PORTION OF
THE PFJ IS CROSSING THE STATE FROM WEST TO EAST...THIS LOW AMPLITUDE
FLOW WILL MOVE SYSTEMS THROUGH THE STATE VERY QUICKLY AND ALLOW FOR A
LOT OF CHANGE OVER THE NEXT FEW DAYS.  AT 500MB THE MAIN LOW CENTER
IS OVER NORTH EASTERN SIBERIA BUT A COLD POCKET NEAR THE MCGRATH
REGION INDICATES THE TROUGH IS INTENSIFYING AND DEVELOPING A
SECONDARY LOW CENTER.  THIS IS REFLECTED IN THE SATELLITE IMAGERY AS
WELL.  THE ASSOCIATED TROUGH STRENGTHENING AND COMBINING WITH AN
UPPER LEVEL VORT MAX TO CREATE A STRONG SOUTHWESTERLY PUSH IN THE
SOUTHCENTRAL REGION. RADAR REFLECTS THIS WELL WITH STRONG ECHOES IN
THE ANCHORAGE BOWL.  EXPECT HEAVY RAINS TODAY SOUTH OF THE ALASKA
RANGE INCLUDING THE SOUTHCENTRAL REGION.  THIS SHOULD HELP CLEAR OUT
THE SMOKE THAT PERVADED THE KENAI PENINSULA AND THE ANCHORAGE BOWL
YESTERDAY.

WEST OF THE ALASKA RANGE MOST OF THE PRECIPITATION HAS ALREADY PASSED
THROUGH AND SKIES ARE BEGINNING TO CLEAR.  MORNING FOG IS A
LIKELIHOOD ALONG THE COAST WITH NORTHWEST FLOW BRINGING THE MARINE
LAYER ONSHORE.  AREAS OF SMOKE WILL STILL BE PRESENT IN THE KUSKOKWIM
VALLEY AND DELTA AND THE NORTHERN PORTIONS OF THE BRISTOL BAY REGION
BUT FOR MOST OF THE AREA NICE WEATHER WILL PREVAIL.

ALONG THE ALEUTIANS WESTERLY FLOW IS BRINGING MORE LOW STRATUS AND
RAIN.  ANOTHER LOW PRESSURE SYSTEM IS MOVING INTO THE REGION BUT IS
JUST BEGINNING TO SHOW THE WHITES OF ITS EYES ON THE SATELLITE.  THIS
SYSTEM IS NOT YET AFFECTING THE ALASKA REGION BUT WILL MOVE THROUGH
THE ALEUTIANS ON MONDAY BRINGING MORE WIND AND RAIN.

MODEL DISCUSSION...MODEL INITIALIZATION SHOWS THAT ALL MODELS ARE
FAIRLY SIMILAR.  HOWEVER THE ETA AND THE ECMWF ARE MOVING THE LOW
PRESSURE SYSTEM THAT IS CURRENTLY SOUTHWEST OF SHEMYA MUCH MORE
RAPIDLY THAN THE GFS AND THE UKMET.  GFS HAS BEEN VERIFYING WELL OVER
THE PAST SEVERAL DAYS AND IS KEEPING GOOD CONTINUITY WITH THE LAST
MODEL RUN.  THEREFORE GFS IS THE MODEL OF THE DAY.

EXTENDED FORECAST...THE LOW PRESSURE SYSTEM CURRENTLY SOUTHWEST OF
SHEMYA WILL STRENGTHEN AND MOVE INTO THE ALEUTIANS ON
MONDAY...REACHING WESTERN ALASKA BY TUESDAY MORNING.  SOUTHWEST FLOW
WILL BRING PLENTY OF MOISTURE TO SOUTHCENTRAL ALASKA AND THE PRINCE
WILLIAM SOUND AHEAD OF THE FRONT...AND WESTERN ALASKA CAN EXPECT
HEAVY RAINS AND SOME GUSTY WINDS ON WEDNESDAY AS THIS STRONG FRONT
MOVES THROUGH.  IN SUMMARY...A RAINY WEEK FOR ALL ZONES.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE WARNING ZONE 172.
FIRE WEATHER...NONE.

*** AUG 05